The present invention relates to a water dispersion type water and oil repellent composition which is excellent in storage stability and which undergoes little change in viscosity even when freezing/thawing cycles are repeated. Particularly, the present invention relates to a water dispersion type water and oil repellent composition which is capable of imparting excellent water and oil resistance to paper constantly.
As a water and oil repellent for paper, a phosphate containing a polyfluoroalkyl group (hereinafter referred to as Rf) is known. Such a water and oil repellent is widely employed, for example, in internal sizing treatment wherein it is incorporated at the time of sheeting paper or size press treatment wherein sheeted paper is dipped.
However, a water dispersion type water and oil repellent composition containing a Rf-containing phosphate as the main component has no adequate storage stability, and the viscosity tends to increase when freezed during storage or during transportation. The water dispersion type water and oil repellent composition having the viscosity thus increased, is incapable of imparting adequate water and oil resistance to paper. Accordingly, with a conventional water dispersion type water and oil repellent composition, it has been necessary to pay an attention to the environment for storage, for example, by controlling the temperature to prevent freezing.
In order to improve the storage stability of a water dispersion type water and oil repellent composition, an oil resistant agent for paper having an anionic surfactant added to a Rf-containing phosphate (JP-A-64-6196) or a water and oil repellent having a fluoroaliphatic hydrocarbon added to a Rf-containing phosphate (JP-A-56-138197) has, for example, been proposed.
By the above proposed improvements, the storage stability has been improved to some extent, but has not yet been practically satisfactory. Further, there has been a problem from the viewpoint of the handling efficiency such that the flash point of the additive itself is low.
The present invention has an object to provide a water dispersion type water and oil repellent composition which is excellent in storage stability and which undergoes little change in viscosity even when freezing/thawing cycles are repeated. Particularly, the present invention has an object to provide a water dispersion type water and oil repellent composition which is capable of imparting excellent water and oil resistance to paper constantly.
The present invention provides a water and oil repellent composition, particularly a water dispersion type water and oil repellent composition, comprising a compound represented by the following formula 1 and the following compound B, as essential components:
[RfQO]m[HO]n[Y+Oxe2x88x92]kPxe2x95x90Oxe2x80x83xe2x80x83Formula 1
provided that the symbols in the formula have the following meanings:
Rf: a polyfluoroalkyl group,
Q: a bivalent organic group,
Y+: (N+HI1R2R3) or an alkali metal cation, wherein each of R1, R2 and R3, which are independent of one another, is a hydrogen atom, xe2x80x94CH2CH2OH, xe2x80x94CH2CH2CH2OH, xe2x80x94CH(CH3)CH2OH or xe2x80x94CH2CH(OH)CH3,
m, n and k: each being an integer, mxe2x89xa71, nxe2x89xa70, kxe2x89xa70, and m+n+k=3;
Compound B: a compound which is miscible with water at any optional ratio and which has a flash point of from 50 to 150xc2x0 C.
The water and oil repellent composition of the present invention contains the compound (hereinafter referred to also as the compound A) represented by the formula 1, as an essential component.
Rf in the compound A represents a polyfluoroalkyl group, which is a group having at least two hydrogen atoms in an alkyl group substituted by fluorine atoms. The carbon number of Rf is preferably from 2 to 20. If the carbon number is less than 2, the oil resistance tends to be low, and if it exceeds 20, the compound tends to be solid at room temperature and have a large sublimation property, whereby handling tends to be difficult. The carbon number of Rf is particularly preferably from 6 to 16. Rf is a straight chain or branched group, preferably a straight chain group. In the case of a branched group, it is preferred that the branch moiety is present at a terminal portion of Rf and the branch moiety is a short chain having a carbon number of from about 1 to 4.
The number of fluorine atoms in Rf is preferably at least 60%, particularly preferably at least 80%, when it is represented by [(number of fluorine atoms in Rf)/(number of hydrogen atoms contained in an alkyl group having the same carbon number as Rf)]xc3x97100(%). Rf is preferably a group having all hydrogen atoms in an alkyl group substituted by fluorine atoms, i.e. a perfluoroalkyl group. Further, Rf is preferably a straight chain perfluoroalkyl group i.e. a group represented by F(CF2)ixe2x80x94 (i is an integer of from 2 to 20), particularly a group wherein i is an integer of from 6 to 16.
Further, Rf may contain a halogen atom other than a fluorine atom. As such other halogen atom, a chlorine atom is preferred. Further, an etheric oxygen atom or a thioetheric sulfur atom may be inserted between a carbon-carbon bond in Rf. The structure of the terminal portion of Rf may, for example, be xe2x80x94CF2CF3, xe2x80x94CF(CF3)2, xe2x80x94CF2H, xe2x80x94CFH2, or xe2x80x94CF2Cl, preferably xe2x80x94CF2CF3.
A specific example of Rf may be C4F9xe2x80x94 including structurally isomeric groups such as F(CF2)4xe2x80x94, (CF3)2CFCF2[F(CF2)4xe2x80x94, (CF3)3Cxe2x80x94 and F(CF2)2CF(CF3)xe2x80x94], C5F11xe2x80x94 [such as F(CF2)5xe2x80x94], Cl(CF2)sxe2x80x94, H(CF2)sxe2x80x94 (s is an integer of from 2 to 5) or (CF3)2CF(CF2)qxe2x80x94 (q is 1, 2, 14), but the following groups are preferred.
C6F13xe2x80x94 [including structurally isomeric groups such as F(CF2)6xe2x80x94, (CF3)2CF(CF2)3xe2x80x94, (CF3)3C(CF2)2xe2x80x94 and F(CF2)4CF(CF3)xe2x80x94], C7F15xe2x80x94 [such as F(CF2)7xe2x80x94], C8F17xe2x80x94 [such as F(CF2)8xe2x80x94], C9F19xe2x80x94 [such as F(CF2)9xe2x80x94], C10F21xe2x80x94 [such as F(CF2)10xe2x80x94], C12F25xe2x80x94 [such as F(CF2)12xe2x80x94], C14F29xe2x80x94 [such as F(CF2)14xe2x80x94], C16F33xe2x80x94 [such as F(CF2)16xe2x80x94], Cl(CF2)txe2x80x94, H(CF2)txe2x80x94 (t is an integer of from 6 to 16), (CF3)2CF(CF2)yxe2x80x94 (y is an integer of from 3 to 13), etc.
A specific example of a case where Rf is a group having an etheric oxygen atom or a thioetheric sulfur atom inserted between a carbon-carbon bond, may be F[CF(CF3)CF2O]hCF(CF3)(CF2)2xe2x80x94, F[CF(CF3)CF2O]kCF(CF3)xe2x80x94, F[CF(CF3)CF2O]j(CF2)2xe2x80x94, F[(CF2)2O]p(CF2)2xe2x80x94, F[CF(CF3)CF2S]hCF(CF3)(CF2)2xe2x80x94, F[CF(CF3)CF2S]kCF(CF3)xe2x80x94, F[CF(CF3)CF2S]j(CF2)2xe2x80x94, F[(CF2)2S]p(CF2)2xe2x80x94, (h is an integer of from 5 to 10, k is an integer of 1 or from 5 or 10, j is 5 or 6, and p is an integer of 1 or from 8 to 11), etc., but the following groups are preferred, wherein r is an integer of from 1 to 4, z is an integer of from 2 to 4, and v is an integer of from 2 to 7.
F(CF2)5OCF(CF3)xe2x80x94, F[CF(CF3)CF2O]rCF(CF3)(CF2)2xe2x80x94, F[CF(CF3)CF2O]zCF(CF3)xe2x80x94, F[CF(CF3)CF2O]z(CF2)2xe2x80x94, F[(CF2)2O]v(CF2)2xe2x80x94.
F(CF2)5SCF(CF3)xe2x80x94, F[CF(CF3)CF2S]rCF(CF3)(CF2)2xe2x80x94, F[CF(CF3)CF2S]zCF(CF3)xe2x80x94, F[CF(CF3)CF2S]z(CF2)2xe2x80x94, F[(CF2)2S]v(CF2)2xe2x80x94, C8F17SO2N(C2H5)xe2x80x94.
Each of m, n and k in the compound A is an integer, mxe2x89xa71, nxe2x89xa70 and kxe2x89xa70, and m+n+k=3. m is preferably 1 or 2, and n is preferably 0.
Q in the compound A is a bivalent organic group and may, for example, be a C2-6 alkylene group or xe2x80x94SO2NR4R5xe2x80x94 (R4 and R5 are a C1-5 alkylene group). Q is preferably xe2x80x94CH2CH2xe2x80x94 or xe2x80x94SO2N(C2H5)CH2CH2xe2x80x94.
Y+ in the compound A is (NH+R1R2R3) or an alkali metal cation. Here, each of R1, R2 and R3 which are independent of one another, is a hydrogen atom, xe2x80x94CH2CH2OH, xe2x80x94CH2CH2CH2OH, xe2x80x94CH(CH3)CH2OH or xe2x80x94CH2CH(OH)CH3. The alkali metal cation may, for example, be Na+. Y+ is preferably (NH+R1R2R3) wherein R1 is a hydrogen atom, and R2 and R3 are xe2x80x94CH2CH2OH.
The following compounds may be mentioned as specific examples of the compound A. In the following compounds, a polyfluoroalkyl group may be any one of structurally isomeric groups and preferably a straight chain group.
[C8F17CH2CH2O]2[(N+H2(CH2CH2OH)2)Oxe2x88x92]Pxe2x95x90O,
[C8F17CH2CH2O][(N+H2(CH2CH2OH)2)Oxe2x88x92]2Pxe2x95x90O,
[C8F17CH2CH2O][HO][(N+H2(CH2CH2OH)2)Oxe2x88x92]2Pxe2x95x90O,
[C6F13CH2CH2O]2[(N+H2(CH2CH2OH)2)Oxe2x88x92]Pxe2x95x90O,
[C6F13CH2CH2O][(N+H2(CH2CH2OH)2)Oxe2x88x92]2Pxe2x95x90O,
[C10F21CH2CH2O]2[(N+H2(CH2CH2OH)2)Oxe2x88x92]Pxe2x95x90O,
[C10F21CH2CH2O][(N+H2(CH2CH2OH)2)Oxe2x88x92]2Pxe2x95x90O,
[C12F25CH2CH2O]2[(N+H2(CH2CH2OH)2)Oxe2x88x92]Pxe2x95x90O,
[C12F25CH2CH2O][(N+H2(CH2CH2OH)2)Oxe2x88x92]2Pxe2x95x90O,
[C8F17CH2CH2O]2[(N+H4)Oxe2x88x92]2Pxe2x95x90O,
[C8F17CH2CH2O][(N+H4)Oxe2x88x92]2Pxe2x95x90O,
[C8F17SO2N(C2H5)CH2CH2O]2[(N+H2(CH2CH2OH) 2)Oxe2x88x92]Pxe2x95x90O,
[C8F17SO2N(C2H5)CH2CH2O][(N+H2(CH2CH2OH) 2)Oxe2x88x92]2Pxe2x95x90O,
[C8F17CH2CH2O]2[(Na+Oxe2x88x92)Pxe2x95x90O.
The compound A in the water and oil repellent composition may be a mixture of two or more compounds. In the case of a mixture of two or more compounds, they may be two or more compounds which are different in m, n or k, or two or more compounds which are different in the carbon number of Rf. The water and oil repellent composition of the present invention contains the compound B as an essential component. The compound B is mixable with water at any optional ratio and has a flash point of from 50 to 150xc2x0 C.
The following compounds may be mentioned as the compound B.
Propylene glycol (hereinafter referred to as PG), ethylene glycol (hereinafter referred to as EG), dipropylene glycol, tripropylene glycol, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, diethylene glycol dimethyl ether, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether monoacetate, tripropylene glycol monomethyl ether, propylene glycol dibutyl ether, tetrapropylene glycol, etc.
As the compound B (the indication in ( ) after the name of a compound shows the flash point), PG (107xc2x0 C.), EG (at least 110xc2x0 C.), dipropylene glycol (137xc2x0 C.), dipropylene glycol monomethyl ether (74xc2x0 C.), tripropylene glycol (at least 110xc2x0 C.), diethylene glycol dimethyl ether (50xc2x0 C.) or diethylene glycol diethyl ether (82xc2x0 C.) is preferred, and particularly preferred is PG. The proportion of the compound B in the water and oil repellent composition is preferably from 3 to 40 mass %, relative to the compound A. If the amount of the compound B is less than 3 mass % relative to the compound A, the effect of the compound B as a stabilizer will not sufficiently be provided, and when freezing/thawing cycles of the water and oil repellent composition is repeated, the increase of the viscosity tends to be large. Further, if it exceeds 40 mass %, when applied to a substrate such as paper, the compound B tends to remain on the surface of the substrate, whereby no adequate water and oil resistance tends to be imparted to the substrate. Further, the viscosity of the water and oil repellent composition tends to be low, and the composition tends to undergo separation during the storage.
Further, the proportion of the compound B in the water and oil repellent composition is preferably from 1 to 10 mass %. Within this range, the viscosity of the water and oil repellent composition is good. The compound B in the water and oil repellent composition may be composed of a single compound or two or more compounds.
The method for preparing the water and oil repellent composition of the present invention is not particularly limited. For example, there may be mentioned a method wherein the compound B is added at the time of preparing the compound A, a method wherein the compound B is added at the time of preparing the compound A, a method wherein the compound B is added at the time of dispersing the compound A in a medium, or a method wherein the compound B is added at the time of adjusting the concentration of the compound A.
For the water and oil repellent composition comprising the compound A and the compound B, it is preferred that the respective components are sufficiently dispersed or mutually solublized by a method such as stirring. At that time, it is preferred to carry out high pressure emulsification treatment by means of e.g. Manton Gorlin, Hydroshare or Microfluidizer. The pressure during the high pressure emulsification is preferably from 10 to 500 kg/cm2, and the temperature is preferably from 30 to 90xc2x0 C.
When high pressure emulsification is to be carried out, preliminary dispersion or emulsification may be carried out, as the case requires, to improve the efficiency of the high pressure emulsification.
To the water and oil repellent composition of the present invention, components other than the above (hereinafter referred to as other components) may be added. Particularly, the water and oil repellent composition of the present invention is of a water dispersion type employing an aqueous medium as described below. Other components may, for example, be preferably a medium other than the compound B, a water and oil repellent other than the compound A, an insecticide, a flame retardant, an antistatic agent or a sizing agent.
The medium other than the compound B is preferably an aqueous medium, such as a medium composed solely of water, or water and a water-soluble organic solvent other than the compound B, particularly preferably solely of water. The amount of the medium is preferably from 50 to 95 mass % in the water and oil repellent composition.
The viscosity of the water and oil repellent composition of the present invention is preferably from 20 to 100 cP at a shear rate of 191.5 sxe2x88x921 at a temperature of 25xc2x0 C. Further, when one cycle comprises storage at xe2x88x9218xc2x0 C. for 12 hours and storage at +40xc2x0 C. for 12 hours, the viscosity after repeating it for five cycles, is preferably from 90 to 110% of the initial viscosity. If the viscosity is less than 20 cP, the dispersion state of the water and oil repellent composition tends to be poor, and if it exceeds 100 cP, handling tends to be difficult.
The water and oil repellent composition of the present invention is excellent in storage stability and undergoes little change in the viscosity even when freezing/thawing cycles are repeated. Particularly when the water and oil repellent composition of the present invention is used for treating a substrate, excellent water and oil resistance can be imparted to the surface of the substrate constantly. The substrate is not particularly limited, but paper, natural leather or synthetic leather is, for example, preferred. The water and oil repellent composition of the present invention is capable of imparting excellent water resistance (the sizing property) and the oil resistance to paper, natural leather or synthetic leather.
In the present invention, the mechanism whereby the change in viscosity of the water and oil repellent composition after repeating freezing/thawing cycles, is little, and the composition is excellent in storage stability, is not clearly understood. However, it is considered that the compound B serves as a dispersant for the compound A, whereby the compound A is associated to prevent a change of the physical state.